Fusion molecule found to cure rheumatoid arthritis in mice

A new fusion molecule, when combined with an anti-inflammatory drug, has been shown to cure rheumatoid arthritis in mice

While advances have been made in treating rheumatoid arthritis, an autoimmune disease causing inflammation of joints in the body, scientists are yet to develop a cure for the disease. But researchers from ETH Zurich, Switzerland have developed a new therapy that has shown to fully cure the condition in mice, leaving the team hopeful of commencing human trials as early as 2015.

The researchers developed a new type of molecule where an antibody is fused with the body’s own immune messenger interleukin (IL-4). When injected, the antibody is drawn to a certain type of protein that only exists in inflamed tissue, taking the IL-4 component along for the ride. Previous studies have established that IL-4 is effective in preventing cartilage and bone damage in mice with rheumatoid arthritis, so merging the two meant that the researchers could target the disease with a new level of precision.

“As a result of combination with the antibody, IL-4 reaches the site of the disease when the fusion molecule is injected into the body,” says Teresa Hemmerle, pharmacist at ETH and lead author of the study. “It allows us to concentrate the active substance at the site of the disease. The concentration in the rest of the body is minimal, which reduces side-effects.”

In testing the new molecule in mice with rheumatoid arthritis, the researchers observed its effects when combined with dexamethasone, an anti-inflammatory drug already used to treat the disease in humans. When administered on their own, both the fusion molecule and dexamethasone worked to slow the progress of the disease. However, when administered at the same time, symptoms such as swollen toes and paws disappeared within a few days.

The scientists also observed the concentrations of various immune messengers in blood and inflamed tissue, which returned to normal levels following treatment with the fusion molecule. They are now preparing to test the drug in human trials, which they hope will begin within the next year.